The present invention relates to a UPC (Usage Parameter Control) circuit and a performance monitoring cell processing circuit arranged in a channel section of an ATM exchange.
The ITU-T (a department for standardizing the telecommunications of the International Telecommunication Union) Recommendation I.610 entitled "The Principles of Operation and Maintenance and Functions of Broadband ISDN" specifies an OAM cell for performance monitoring of the ATM connection and a method thereof. A method of performance monitoring is also studied and commented in "A Study of VP Transmission Quality Monitor System Using Variable-Length Block in ATM Network" by Ohta, et al., Shingaku Technical Journal CS92-31.